Friday, March 26, 2010

Ratio P6 A002

In a bag of notes, the number of $2, $5 and $10-notes are in ratio of 22 : 7 : 3. 5/11 of the $2-notes and 71 of $5-notes are taken out. The remaining notes are worth $624. How many $10-notes are there?

Original number of $2 is 22 units. So convert the remaining fraction in order to compare to 22 units.

5/11 x 2/2 = 10/22

Convert the 71 $5 notes to amount.

71 x 5 = $355

$2 $5 $10 Total

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22 :7 : 3

- 10 -$355

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12 : 7 - $355 :3

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24 35 - $355 30 $624Convert number of notes

------------------------------------------ to amount.

24 + 35 + 30 = 89

89 u --> 624 + 355 = 979

1 u --> 979 ÷ 89 = 11

3 u --> 3 x 11 = 33

If you are worried that marks may be deducted, you can always find 30 u to get $330. Then divide by 10 to get 33 $10 notes.